20131320 has 128 divisors (see below), whose sum is σ = 66977280. Its totient is φ = 4800000.

The previous prime is 20131313. The next prime is 20131339. The reversal of 20131320 is 2313102.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20131296 and 20131305.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 133245 + ... + 133395.

It is an arithmetic number, because the mean of its divisors is an integer number (523260).

Almost surely, 2^20131320 is an apocalyptic number.

20131320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20131320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33488640).

20131320 is an abundant number, since it is smaller than the sum of its proper divisors (46845960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20131320 is a wasteful number, since it uses less digits than its factorization.

20131320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277 (or 273 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 20131320 is about 4486.7939555990. The cubic root of 20131320 is about 272.0345616405.

Adding to 20131320 its reverse (2313102), we get a palindrome (22444422).

It can be divided in two parts, 2013 and 1320, that added together give a palindrome (3333).

The spelling of 20131320 in words is "twenty million, one hundred thirty-one thousand, three hundred twenty".